Turns out that Zeus is alive and well despite rumors of its "death" or morph into the SpyEye Trojan. "...We're still seeing both distinct malware families out and about in the wild. Between the two, we're finding that they're responsible for a significant amount of the e-commerce-related fraud happening at any given time," wrote Matt McCormack of the Microsoft Malware Protection Center in Melbourne, Australia.
Microsoft snuck more protections from new Zeus malware variants into the latest version of its Malicious Software Removal Tool (MSRT), he said in a blog post today: "This month (carefully hidden under the Win32/Bamital blanket), employing the old adage 'fight fire with fire', we decided to fight sneakiness with sneakiness and quietly slipped a fairly major Win32/Zbot update into MSRT."
The software giant detected 103,391 Zeus-infected machines in March; 113,814 in April; 60,385 in May; 83,555 in June; 61,323 in July; and 89,994 in August.
McCormack said in his post that Microsoft "felt it was time to turn the screws tighter on Zbot again" given the steady stream of infections this year.
Security researchers have been closely watching for samples of a merged version of Zeus and SpyEye ever since "Slavik" or "Monstr," the author of Zeus, last year gave the source code to another crimeware author, "Gribodemon," a.k.a. "Harderma."
Trend Micro researchers earlier this year got their hands on a sample of the SpyEye builder that included an administration panel including some lines of Zeus code. The two malware families would make a powerful combination: While Zeus was able to remove some security applications, SpyEye was not.
Meanwhile, the source code for SpyEye was published on the Web in August, making it easily attainable and adaptable by cybercriminals. "One of the most dangerous Swiss Army knives in malware is now available to billions," Sean Bodmer, senior threat intelligence analyst at security vendor Damballa, said last month in the wake of the SpyEye leak.
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